Digital television, popularly referred to as DTV, is an enhanced television system capable of transmitting and receiving digitized signals, displaying digital images and playing digital audio. While some of these features may be present in current analog television systems such as national television standards committee (NTSC), SEquential Couleur Avec Memoire (SECAM) and Phase Alternate Line (PAL), the combination of digitized transmission, reception, video and audio distinguishes digital television from current analog television systems.
Digital television employs various digital signal processing techniques and utilizes scarce bandwidth in a more spectrally efficient manner to transport and present audio and video signals in a way that is superior to current analog television systems. In this regard, digital television allows more channels containing more information to be broadcasted within an equivalent bandwidth utilized by current analog television systems. Accordingly, any excess bandwidth can be re-allocated for use by other types of communication systems. Broadcasters utilizing digital television systems are therefore, capable of providing over-the air television signals containing higher picture resolutions than current analog broadcast television systems
Broadcasters utilizing digital television systems may also have the capability to provide multicasting and datacasting services using the same bandwidth allocated for conventional analog television systems. For these reasons, Congress mandated that current broadcast television service must, in time, be completely converted to digital television. While digital television (DTV) utilizes the same broadcast very high frequency (VHF) spectral band and ultra-high frequency spectral (UHF) band as conventional television broadcasting systems, digital television utilizes different modulation techniques than conventional analog television broadcasting systems. Conventional analog television broadcasting systems modulate video using amplitude modulation (AM) and the accompanying audio is modulated using frequency modulation (FM). DTV utilizes a plurality of modulation techniques for transmitting and receiving packetized digital signals. In the United States of America, an eight level vestigial sideband (VSB) modulation scheme is utilized. In some regions of Europe and Asia, for example, coded orthogonal frequency division multiplexing is the modulation scheme of choice. On the other hand, digital satellite systems (DSS) utilize quadrature phase shift keying, while cable television (CATV) system utilizes quadrature amplitude modulation (QAM).
In the United States, a plurality of broadcast formats promulgated by the Advanced Television Standards Committee (ATSC) has been adopted for DTV applications. Some of these formats comprise progressive-scan video comprising 480 scan lines referred to as 480p, interlaced 4:3 video having 480 scan lines referred to as 480i, interlaced video having 1080 scan lines referred to as 1080i and progressive-scan video having 720 scan lines referred to as 720p. Standard definition (SD) television (SDTV) utilizes the interlaced 480i and progressive 480p formats. The picture quality provided by SDTV is comparable in certain respects to conventional NTSC 525 lines systems. High definition (HD) television (HDTV) utilizes the interlaced 1080i and progressive 720p formats in 16:9 aspect ratio. The resolution of the HDTV interlaced 1080i and progressive 720p formats may be converted to lower resolution such as the interlaced 480i and progressive 480p formats provided by SDTV.
In the US for example, DTV signals are modulated on an RF carrier using 8-level VSB or 8VSB, and transmitted in a six (6) MHz channel as compressed 4:2:0 MPEG-2 formatted packetized streams. These packetized streams contain both audio and video information. For this reason, a conventional analog system is unable to receive a transmitted DTV signal. In order to decode a received 8-level VSB signal, an ATSC-compliant DTV receiver or a set-top box is required.
While broadcast television service is improving as it transitions to digital television format, television and video display manufacturers are also improving the display characteristics and quality of their products. For example, HDTV equipment with improved resolution and video processing capabilities are now being marketed from numerous manufacturers. Such HDTV equipment may implement various signal processing techniques that improve the display quality of the received signal. However, in instances when the input video signal is not significantly degraded, it may be difficult for an end user to distinguish between, and select which processing technique, or a combination of processing techniques, to use to improve the signal quality.
Modern televisions may be enabled to apply a variety of video signal processing techniques, such as sharpness adjustment, noise reduction, color adjustment, and/or ghost cancellation. However, unless the input video signal is deteriorated, it may be difficult for an end user to notice the effects of the video signal processing techniques.
Further limitations and disadvantages of conventional and traditional approaches will become apparent to one of skill in the art, through comparison of such systems with some aspects of the present invention as set forth in the remainder of the present application with reference to the drawings.